Bending restrictor assembly for permanently bending and restraining ovality of a subsea pipe

Abstract

A bending restrictor assembly has a pipeline section, a first overlying pipe section having a wall overlying a portion of the pipeline section at one end thereof, a second overlying pipe section having a wall overlying another portion of the pipeline section at an opposite end thereof, and a plurality of cylindrical members overlying the pipeline section between the first and second overlying pipe sections. The first and second overlying pipe sections extend outwardly beyond the respective ends of the pipeline section. The bending restrictor assembly achieves a permanent bend and restricts ovality of a subsea pipe.

I claim: 
     
       1. A bending restrictor assembly for permanently bending and restraining ovality of a subsea pipe, the bending restrictor assembly comprising:
 a pipeline section having an outer diameter, a first end and a second end; 
 a first overlying pipe section having a wall overlying a portion of said pipe section at the first end, said first overlying pipe section having an outer diameter greater than the outer diameter of said pipeline section; 
 a second overlying pipe section having a wall overlying another portion of said pipeline section at the second end, said second overlying pipe section having an outer diameter greater than the outer diameter of said pipeline section; and 
 a plurality of cylindrical members overlying said pipeline section between said first and second overlying pipe sections, said plurality of cylindrical members being translatable along said pipeline section as said pipeline section is bent so as to allow said pipeline section to bend beyond an elastic limit of said pipeline section so as to achieve a permanent bend of said pipeline section. 
 
     
     
       2. The bending restrictor assembly of  claim 1 , said first overlying pipe section having an end extending outwardly beyond the first end of said pipeline section, said second overlying pipeline section having an end extending outwardly beyond the second end of said pipeline section. 
     
     
       3. The bending restrictor assembly of  claim 2 , said first overlying pipe section having a wall thickness beyond the first end of said pipeline section that is greater than a wall thickness of the wall that overlies the portion of said pipeline section, said second overlying pipe section having a wall thickness beyond the second end of said pipeline section that is greater than a wall thickness of the wall that overlies the another portion of said pipeline section. 
     
     
       4. The bending restrictor assembly of  claim 1 , each of said first and second overlying pipe sections having an outer diameter that matches an outer diameter of said plurality of cylindrical members. 
     
     
       5. The bending restrictor assembly of  claim 1 , said first overlying pipe section having an abutment surface over said pipeline section, said second overlying pipe section having another abutment surface over said pipeline section, said plurality of cylindrical members positioned between the abutment surfaces. 
     
     
       6. The bending restrictor assembly of  claim 5 , said first overlying pipe section having a flange extending radially outwardly therefrom adjacent said abutment surface thereof, said second overlying pipe section having another flange extending radially outwardly therefrom adjacent said another abutment surface. 
     
     
       7. The bending restrictor assembly of  claim 6 , said plurality of cylindrical members having a first cylindrical member adjacent said abutment surface of said first overlying pipe section, said plurality of cylindrical members having a second cylindrical member adjacent said another abutment surface of said second overlying pipe section. 
     
     
       8. The bending restrictor assembly of  claim 7 , said first cylindrical member having a flange at an end thereof adjacent said flange of said first overlying pipe section, said second cylindrical member having another flange at an end thereof adjacent said another flange of said second overlying pipe section. 
     
     
       9. The bending restrictor assembly of  claim 8 , said flange of said first cylindrical member being joined to said flange of said first overlying pipe section with a first tension member, said another flange of said second cylindrical member being joined to said flange of said second overlying pipe section with a second tension member, each of said first and second tension members limiting an amount of separation between the cylindrical member and the overlying pipe section. 
     
     
       10. The bending restrictor assembly of  claim 1 , said first and second overlying pipe sections being in liquid-tight relation with said pipeline section. 
     
     
       11. The bending restrictor assembly of  claim 1 , said plurality of cylindrical members having a space therebetween when said pipeline section is straight, said plurality of cylindrical members having a portion of abutting each other when said pipeline section is bent. 
     
     
       12. The bending restrictor assembly of  claim 1 , said plurality of cylindrical members having a tension member between adjacent cylindrical members, said tension member limiting amount of space between the adjacent cylindrical members when said pipeline section is bent. 
     
     
       13. The bending restrictor assembly of  claim 12 , each cylindrical member of said plurality of cylindrical members having a first flange at one end thereof and a second flange at an opposite end thereof, said tension member being affixed to said first and second flanges. 
     
     
       14. The bending restrictor assembly of  claim 1 , each of said first and second overlying pipe sections having a maximum wall thickness that is greater than a wall thickness of a wall of said pipeline section. 
     
     
       15. The bending restrictor assembly of  claim 1 , further comprising:
 a first pipeline affixed to an end of said first overlying pipe section that extends outwardly of said pipeline section; and 
 a second pipeline affixed to an end of said second overlying pipe section that extends outwardly of said pipeline section. 
 
     
     
       16. The bending restrictor assembly of  claim 15 , said first pipeline having a wall thickness matching a wall thickness of said first overlying pipe section at the end of said first overlying pipe section that extends outwardly of said pipeline section, said second pipeline having a wall thickness matching a wall thickness of said second overlying pipe section at the end of said second overlying pipe section that extends outwardly of said pipeline section. 
     
     
       17. A bending restrictor assembly for permanently bending and restraining ovality of a subsea pipe, the bending restrictor assembly comprising:
 a pipeline section having an outer diameter, a first end and a second end; 
 a first overlying pipe section having a wall overlying a portion of said pipe section at the first end, said first overlying pipe section having an outer diameter greater than the outer diameter of said pipeline section; 
 a second overlying pipe section having a wall overlying another portion of said pipeline section at the second end, said second overlying pipe section having an outer diameter greater than the outer diameter of said pipeline section; and 
 a plurality of cylindrical members overlying said pipeline section between said first and second overlying pipe sections, said first overlying pipe section being shrink-fit onto said pipeline section such that an inner wall of said first overlying pipe section bears against the outer diameter of said pipeline section, said second overlying pipe section being shrink-fit onto said pipeline section such that an inner wall of said second overlying pipe section bears against the outer diameter of said pipeline section. 
 
     
     
       18. A bending restrictor assembly comprising:
 a pipeline section having a first end and a second end; 
 a first overlying pipe section having a wall overlying a portion of said pipeline section at the first end thereof, said first overlying pipe section extending outwardly beyond said first end of said pipeline section, said first overlying pipe section having a maximum wall thickness that is greater than a wall thickness of said pipeline section; 
 a second overlying pipe section having a wall overlying another portion of said pipeline section at the second end thereof, said second overlying pipe section extending outwardly beyond the second end of said pipeline section, said second overlying pipe section having a maximum wall thickness that is greater than a wall thickness of said pipeline section; and 
 a plurality of cylindrical members overlying said pipeline section between the first and second overlying pipe sections, said plurality of cylindrical members allowing said pipeline section to bend beyond an elastic limit and to restrain ovality of said pipeline section so as to achieve a permanent bend and to prevent collapse of said pipeline section.